Heat exchangers are often used as condensers and evaporators in air conditioning systems. The heat exchanger selected for a particular application is often based on a high load or an average load. Thus, when a system operates outside the condition for which it was designed, the heat exchanger may encounter problems (e.g., vapor provided in a liquid exit line, liquid provided in a vapor exit line, etc.) and/or an efficiency of the system may be less than optimal.
Another problem is that two-speed or variable heat exchangers may be able to run in high and low running states but do not normally use a variable charge (the level of refrigerant). The charge may be set for a value between the high and low states because the amount of refrigerant cannot be changed easily. As a result the amount of charge may not be chosen for the greatest efficiency. An inappropriate charge level can lead to excess gas and/or fluid in a system. In practice, because the charge level cannot be changed easily, heating and cooling systems are built to handle some excess gas and/or fluid depending on the high and low running states and the desired charge. Even so, these inefficiencies can lead to unwanted mechanical failures and inefficient use of resources or energy.
Another problem in the prior art is that, when a system is operating outside of a desired range or inefficiently, a mix of liquid and gas may pass through the heat exchanger. Certain portions of manifolds, along the edges of a heat exchanger may need certain amounts of liquid to collect at certain portions. And when insufficient or excess liquid collects it can cause problems in the system. With insufficient cooling, excess gas may be left in the system and may collect in certain areas of the system. This increases the likelihood of mechanical failure.
Because heat exchangers can be limited in the preset options or variables, they can often be poorly calibrated for how they're used in practice. Users may put heat exchangers under variable loads that the exchangers could not be calibrated for ahead of time.